1. Technical Field
The present disclosure relates to a method for making a thermal interface material.
2. Description of Related Art
Electronic components such as semiconductor chips are becoming progressively smaller, while at the same time heat dissipation requirements thereof are increasing. Commonly, a thermal interface material is utilized between the electronic component and an integrated heat spreader to dissipate heat generated by the electronic component. However, the performance of the thermal interface material is restricted by a heat conduction coefficient thereof. Heat conduction coefficients of thermal interface materials are now considered to be too low for many contemporary applications.
Conventional thermal interface materials are metallic. However, the metallic materials tend to have a much higher coefficient of thermal expansion than semiconductor devices. Mechanical stresses are induced during temperature cycling and tend to overstress the electronic component, which can potentially leads to failures.
Referring to FIG. 4, a typical thermal interface material 60 is a composite material obtained by diffusing a plurality of carbon nanotubes 64a in a polymer 62. The plurality of carbon nanotubes 64a forms a carbon nanotube array 64. The carbon nanotubes 64a in the carbon nanotube array 64 are parallel to each other and provide a heat conduction path in the polymer 62. Opposite ends of the carbon nanotubes 64a are exposed from the polymer 62. Usually, the thermal interface material 60 is made by a method of injection molding. In use, the thermal interface material 60 is located between an electronic component 66 and a cooling device 68. However, a dissipation surface 662 of the electronic component 66 is smaller than a dissipation surface 682 of the cooling device 68. Therefore, some of the carbon nanotubes 64a cannot establish a heat conduction path between the electronic component 66 and the cooling device 68, thus the heat conduction coefficient of the thermal interface material 60 is relatively low.
What is needed, therefore, is to provide a method for making a thermal interface material with a high heat conduction coefficient.